Pushing glass

[vakkotaur]

I've had a small telescope mirror in the midst of being polished for, well, for way too long now. Last night I finally got around to finding a place to order pitch (for a proper polishing lap) and cerium oxide (polishing compound) and ordering. I have some pitch, but don't trust it to be free of scratch-causing contaminants and I'm about out of cerium oxide. So I ordered enough of both to last me a while, at least for any more small mirror I might make.

I do have some small Pyrex blanks, so there likely will be some more mirrors in the future. I'll need more grit to grind them, but that can wait. Finishing this one comes first - and it looks like it's not just too far from being done, really.

On a whim, I poked around eBay last night as well. I found a porthole glass with only under a day to go on the auction. It's just the glass, not the brass housing most folks seem to want. The Buy-It-Now price wasn't great, but the opening bid wasn't too bad so I put in a low bid and expected to be outbid. Evidently most folks looking at portholes want the brass housing and such. So now I will be getting a 12.5 inch diameter 0.75 inch thick (that's 0.25 inches thicker than I've seen some vendors sell) piece of glass. Whatever I use it for, it won't be for a while. But I when I do decide to get on with making something that size, it'll be there.